The invention relates to a device for controlling the positioning of an observer moving over a plane at a parking position (P) located at a distance (d) from a fixed reference point (o).
The invention applies particularly to the positioning of an aircraft in a parking area.
In airports, it is necessary to place the aircraft at clearly defined parking positions. This is particularly the case when the airport includes satellite boarding stations equipped with telescopic gangways which are brought to a position against the door of the aircraft. Actually, even if it is possible to adjust the position of the final portion of the gangway, this can only be done within fairly tight limits. On the other hand, several aircraft are often placed around the same satellite station, and, in this case, it is obvious that the parking positions of the aircraft must be adhered to with a fair degree of accuracy.
Until now, very simple but relatively imprecise methods have been used for guiding pilots to their parking position.
One of these methods which is currently in use consists in guiding the aircraft along an approach line right up to the point of parking which is indicated to the pilot by means of a reference point. For example, the approach line is a straight line passing through the parking position (P) and through a reference point (O), and this may in practice be provided either on the ground, or by using alignment of two reference points, e.g., lights, which are spaced from each other. The pilot keeps to this line while observing the alignment and stops when a second alignment indicates to him that he has arrived at his parking position. Consequently, the pilot must look in two directions, which is a somewhat difficult procedure in practice. Alternatively, the two alignments are provided in practice by reference points which, normally, may not be very distant from each other, and consequently the alignment which gives the position for parking only forms a fairly small angle with the line of approach. The result of this is that an error of judgement by the pilot may result in a fairly large difference in position with respect to the fixed parking position (P).
The invention provides a device for parking stations in airports which, without being excessively cumbersome or expensive, allow pilots to park their aircraft with a high degree of accuracy.